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Load transmission between slabs and shores during the construction of RC building structures A review

  • Buitrago, Manuel|||0000-0002-5561-5104
  • Adam, Jose M|||0000-0002-9205-8458
  • Moragues, Juan J
  • Calderón García, Pedro Antonio
[EN] Shoring successive floors is at present the most frequently used technique when constructing reinforced concrete (RC) building structures. This technique allows the recently poured slabs to be supported by the lower slabs by means of shores. Considering the particular characteristics of shoring successive floors, it is very important to be able to estimate how loads are transmitted between shores and slabs in order to maintain adequate structural safety and avoid situations of risk or even collapse in buildings under construction. The transmission of loads from shores to slabs during all the construction stages is a complex phenomenon and has been the subject of numerous studies, especially in recent years. The research carried out to date has included experiments on fullscale buildings and the development of advanced numerical models, the estimation of the loads acting on slabs during construction, the definition of simplified calculation methods to estimate loads on slabs and shores during building construction and estimating the appropriate construction times taking into account the evolution of the mechanical properties of early-age concrete. This paper was conceived in order to give an answer to: (1) advances in the field of constructing RC building structures, (2) the growing interest of the scientific community, and (3) the need for the structural and construction engineering sector to have the tools available to increase the safety and design of building construction processes. The paper is unique in the field of RC building structures in that it is the widest, most complete and most ambitious review carried out to date and includes the most important advances in the study of slab-shore load transmissions. This work will be of interest to researchers who wish to go deeper into the field of building construction, and to more experienced professionals who require all the up-to-date information in a single document. However, engineers, architects and builders could also find the paper an excellent guide that will help them to improve their daily work in the field of designing and constructing buildings., The authors would like to express their gratitude to the Spanish Ministry of Education, Culture and Sport for funding received under the FPU Program [FPU13/02466] and also to the Generalitat Valenciana [GV/2015/063].

Functional, Thermal and Rheological Properties of High Fibre Fresh Pasta: Effect of Tiger Nut Flour and Xanthan Gum Addition

  • Martín-Esparza, M.E.|||0000-0002-0066-6748
  • Raigón Jiménez, Mª Dolores|||0000-0001-8055-2259
  • Raga-Soriano, Ana
  • Albors, A.|||0000-0002-7713-9401
[EN] Tiger nut flour (TNF) is a rich source of dietary fibre with potential to be used in cereal-based products. However, research on improving the rheological properties of tiger nut-based doughs is limited. In this paper, the significance of TNF and xanthan gum (X) incorporation into fresh egg pasta, in terms of its thermal and dynamic rheological properties, has been investigated. Plain semolina pasta (DWS) was used as control. High fibre doughs (20 and 40% TNF) with or without X (0 and 1%) were assessed. Both fundamental (dynamic oscillatory and creep tests) and empirical (texture profile analysis) tests were performed to assess the viscoelasticity of TNF-DWS composite blends. Raw solids (TNF, DWS) were characterised in terms of their chemical composition, particle size distribution and functional properties. For both fresh and cooked pasta, water activity, water content and gelatinisation temperatures were estimated. The results from the rheological tests revealed that partial replacement of DWS by TNF lead to less cohesive and weaker structures due to the lower presence of a gluten network. X significantly improved the rheological response of the TNF-based doughs. Thermal analysis showed a single endothermic peak in the temperature range between 60 and 78 degrees C during heating, which corresponds to the amylopectin gelatinisation. However, when replacing 40% of DWS by TNF, two-phase transitions were observed, probably associated to the starch tiger nut gelatinisation or the formation of amylose-lipid complexes. The optimum cooking time for the tiger nut pasta was 2min as determined by a calorimetric analysis., This work was supported by the Conselleria de Empresa, Universidad y Ciencia (Spain) throughout the project AICO/2016/056. Authors are thankful to Harinas Villamayor S.A. for providing raw materials for conducting this study.

Load limiters on shores: Design and experimental research

  • Buitrago, Manuel|||0000-0002-5561-5104
  • Adam, Jose M|||0000-0002-9205-8458
  • Calderón García, Pedro Antonio
  • Moragues, Juan J
[EN] When constructing reinforced concrete building structures, shores are normally used to transmit the loads from freshly poured slabs to lower floors. However, certain problems are involved in this process, including: (a) the loads on the shores may be higher than expected, which can lead to the collapse of the shoring system or even of the whole structure, and (b) the limited range of shore types in commercial catalogues, which often means that the shores used are oversized. This paper describes the study carried out on the development of a new loadlimiter (LL) that can be fitted to shores to improve safety and reduce the cost of constructing building structures. The study shows that combining mechanical and civil engineering fields made it possible to produce a novel device that could revolutionise the shoring techniques at present in use. The method of designing and implementing the LLs involved: (a) the design of prototypes by using numerical simulations, (b) the use of the design of experiments technique, (c) an ambitious experimental campaign in which LL were tested, (d) the detailed simulation of the final design, and (e) the formulation of a simplified model that considers the behaviour of the shore-LL as a unit., The authors would like to express their gratitude to the Spanish Ministry of Education, Culture and Sport for funding received under the FPU Program [FPU13/02466], also to the Generalitat Valenciana [GV/2015/063] and to Professor Salvador Ivorra from University of Alicante for helping us to carry out the steel characterization tests.

Study of the frequency factor in the thermal desorption of astrophysical ice analogs: CH4, C2H4, C2H6, CH3OH, CO, CO2, H2O and N2

  • Luna Molina, Ramón
  • Domingo Beltran, Manuel
  • Millán Verdú, Carlos
  • Santonja Moltó, Mª Del Carmen
  • Satorre, M. Á.
[EN] In this work the frequency factor and the influence of the temperature on this parameter, for zeroth order desorption processes, has been experimentally determined for eight molecules of astrophysical interest. In the literature, this parameter has been estimated indirectly, obtaining values that differ by as much as three orders of magnitude from different authors. As a consequence, there are very different desorption rates reported for the same molecule and additionally its temperature dependence has been systematically neglected. The frequency factor is widely used to model the dynamics of these species under low temperature conditions present in some astrophysical environments. The method reported in this work is based on the analysis of the signal of a quartz crystal microbalance acting as a sample-holder, which is able to directly detect molecules desorbing from it. Two different types of desorption experiments were necessary for this study. In a first set of experiments, carried out at a constant rate of warming up, the desorption energy is obtained. The second set of experiments were performed at several constant temperatures to calculate the frequency factor and its relationship with temperature. The reasons for some anomalous behaviour have been analyzed. The dependence of the frequency factor on temperature should be taken into account when the Polanyi-Wigner equation is used for desorption processes. Every molecule has to be independently studied as no global tendency is found for the variation of the frequency factor with temperature. (C) 2018 Elsevier Ltd. All rights reserved., This work was supported by the Plan Nacional FIS2013-48087-C2-2-P and FIS2016-77726-C3-3-P of the Ministerio de Economia y Competitividad (co-financed by FEDER funds).

Freeze dried quince (Cydonia oblonga) puree with the addition of different amounts of maltodextrin: physical and powder properties

  • Ünlüeroğlugil, Özle
  • Yüksel, Hira
  • Çalışkan Koç, Gülşah
  • Dirim, Safiye
[EN] This study aims to determine the drying behavior of quince puree and as an adverse effect powdered sugar added quince puree with the addition of maltodextrin. The addition of powdered sugar increases the drying time and the total amount of energy and the same time slightly decreases the moisture content and water activity values. The color values and the properties on these values changed both with the addition of maltodextrin and powdered sugar. The density values, flow properties and reconstitution properties are significantly affected by the amount of maltodextrin in plain or powdered sugar added samples. Keywords: quince, freeze-drying, maltodextrin, powder properties

Influence of freeze-drying conditions on orange powder flowability

  • Usganda, Mariana
  • Silva Espinoza, Marilú Andrea
  • Egas, Luis
  • Camacho, María del Mar
  • Martínez-Navarrete, Nuria
[EN] Freeze-drying may be a good alternative to get less perishable fruit products. The objective of the present study was to evaluate the impact of freeze-drying conditions of an orange puree on some flow related and rehydration properties of the obtained powders. The results showed that the application of heat during freeze-drying does not affect the parameters studied. However, the partial dehydration of the initial sample results in a lesser porosity and wettability values., The authors thank the Ministerio de Economía, Industria y Competitividad for the financial support given through the Project AGL 2017-89251-R (AEI/FEDER-UE) and the Ministerio of Educación, Cultura y Deporte for the FPU grant (FPU14 / 02633) granted to Ms. Andrea Silva.

Process of parboiling rice by microwave-assisted hot air fluidized bed technique

  • Prachayawarakorn, Somkiat
  • Saniso, E.
  • Swasdisewi, T.
  • Soponronnarit, S.
[EN] In this work the new process of producing parboiled rice (PB) by combinatintion of microwave and hot air fluidized bed (MWFB) was proposed and investigated. Results showed that the drying time was shorter with smaller bed depth, higher drying temperature and higher microwave power. The initial grain temperature, drying temperature, bed depth and microwave power strongly affected the gelatinization of rice starch. The PB produced by MWFB caused a very small broken kernel (1-2%). The whiteness was decreased with increase in drying time, initial grain temperature, drying temperature and microwave power. The specific energy consumption was increased with increasing such operating parameters., The authors express their sincere appreciation to The Office Of The Higher Education Commission (OHEC) and Yala Rajabhat Universisty (YRU), Thailand. Also, the authors thanks to The Thailand Research Fund (TRF) and The Thailand Research Fund (Grant no. DPG5980004), for their financial support.

Modeling sorption isotherms and isosteric heat of sorption of roasted coffee beans

  • Collazos-Escobar, Gentil
  • Gutiérrez-Guzmán, Nelson
  • Vaquiro-Herrera, Henry
  • Cortes-Macias, Erika
[EN] The aim of this work was determine the sorption isotherms in roasted beans of specialty coffee at temperatures of 25, 30 and 40 °C and water activities between 0.1 and 0.8 using the dynamic dew point method. The experimental sorption data were modeled using 12 different equations to represent the dependence of equilibrium moisture content with aw and temperature. The net isosteric heat of sorption was determined from the experimental sorption data using the Clausius-Clapeyron equation. The Weibull model satisfactorily modeled the effect of the temperature on the hygroscopic equilibrium in roasted coffee beans (R2adj =0.902 and RMSE = 0.00550 kg·kg-1d.b.). The net isosteric heat of sorption increase with increased moisture content.

Organic apples (cv. Elstar) quality evaluation during hot-air drying using Vis/NIR hyperspectral imaging

  • Shrestha, Luna
  • Moscetti, Roberto
  • Crichton, Stuart
  • Hensel, Oliver
  • Sturm, Barbara
[♥EN] Organic dried apples are common snacks fulfilling functional as well as nutritional aspects. However, appearance of dried slices does not always satisfy consumer requirements, thus, improvements are needed. In this study, partial least squares (PLS) regression models were successfully developed to monitor changes in colour and moisture content in apple slices during the drying process over the Vis/NIR spectral range. The regression vector analysis results suggested that features at 580, 750 and 970 nm are better for predicting moisture content, while 580 and 680 nm allow to measure the (a*/b*) colour ratio., The authors gratefully acknowledge CORE Organic Plus for financial support through the SusOrganic project titled: ‘Development of quality standards and optimized processing methods for organic produce’ (Nr: 2814OE006)

Description of atmospheric freeze-drying of brown seaweeds (Saccherina Latissima) with respect to thermal properties and phase transitions

  • Tolstorebrov, Ignat
  • Eikevik, Trygve
  • Petrova, Inna
  • Bantle, Michael
[EN] Thermal properties of brown seaweeds (Saccharina latissima) were determined using DSC technique in the temperature range between -150.0 and 50.0 °C. The following phase transitions were detected: glass transitions, incipient point of ice melting and freezing point. The ice content and amount of unfrozen water was detected by analysis of the melting peak. The ice content reduction in the product was predicted for different moisture contents and temperatures for atmospheric freeze-drying process, Mobility of the scientists from Murmansk State Technical University was provided by financial support of SIU, High North Programme 2015 (HNP-2015/10053)

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